Problem/Bug Nothing happens when I issue a comand

I'm trying to build a server on 1.8 but nothing happens when I issue a command in the chat.
Console says: "(My Nick) issued server command: /(command)" and nothing else. Few moments after I run the server, this message appears repeatedly in the console:

Code:

[21:00:13 WARN]: [Essentials] EssentialsTimer Error:
java.lang.NullPointerException
        at com.earth2me.essentials.perm.PermissionsHandler.getName(PermissionsHandler.java:153) ~[EssentialsX-2.17.2.0.jar:?]
        at com.earth2me.essentials.User.isAuthorizedCheck(User.java:117) ~[EssentialsX-2.17.2.0.jar:?]
        at com.earth2me.essentials.User.isAuthorized(User.java:93) ~[EssentialsX-2.17.2.0.jar:?]
        at com.earth2me.essentials.User.checkActivity(User.java:646) ~[EssentialsX-2.17.2.0.jar:?]
        at com.earth2me.essentials.EssentialsTimer.run(EssentialsTimer.java:58) [EssentialsX-2.17.2.0.jar:?]
        at org.bukkit.craftbukkit.v1_8_R1.scheduler.CraftTask.run(CraftTask.java:53) [craftbukkit.jar:git-Bukkit-33d5de3]
        at org.bukkit.craftbukkit.v1_8_R1.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:349) [craftbukkit.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:668) [craftbukkit.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:284) [craftbukkit.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:609) [craftbukkit.jar:git-Bukkit-33d5de3]
        at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:517) [craftbukkit.jar:git-Bukkit-33d5de3]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_231]

Only the commands "/say" and "/login" work. Messages appear when I type, and plugins seem to work (at least the ones that don't require any chat commands).
Commands I issue in the console also don't work.
When I issue a command that doesn't exist, it obviously says "Unknown command. Type "/help" for help.".
Thanks for all help.

 

https://pastebin.com/kimkrXhM
It's the log that I logged in, tried some commands and left.

 

@timtower Umm I didn't get it, it says it's available for 1.8? If not, what do you suggest?

I've installed Bssentials for 1.8, and still, some commands do the same thing (most of them work). And there's no GroupManager or something like that. Is it about Bssentials or my server?

EDIT by Moderator: merged posts, please use the edit button instead of double posting.